This invention relates to a multi-fuel carburetor and more particularly to an improved construction for such a carburetor.
The use of multi-fuel engines is well known. Normally, the engine is operated on one fuel during a certain running condition and on another fuel during other running conditions. For example, it is known to operate outboard motors or other marine engines with kerosene or alcohol as the main fuel. However, a higher quality fuel such as gasoline is employed for such running conditions as starting, idle or during acceleration. Conventionally, the fuels are supplied by a multi-fuel carburetor that has a main fuel bowl in which the kerosene or alcohol is contained and an auxiliary fuel bowl in which the gasoline is contained. The different fuels are supplied to the same induction passages by different, or at times, common fuel discharge circuits. With multi-fuel carburetors of the type heretofore known, it has been the common practice to employ external plumbing or piping so as to supply the various fuel circuits, particularly from the auxiliary fuel bowl. Such arrangements obviously result in complicated carburetor constructions and the likelihood of damage or difficulties during servicing.
It is, therefore, a principle object of this invention to provide an improved, simplified multi-fuel carburetor.
It is a further object of this invention to provide a multi-fuel carburetor in which the external plumbing is reduced.
When multiple fuels are employed, it is desirable to insure against the discharge of the auxiliary fuel under running conditions when it is not required. For example, it is desirable to cut off the flow of gasoline when the engine is operating at a steady state, off idle condition. Although various devices have been proposed for this purpose, they are not always satisfactory, particularly when a single fuel bowl serves multiple induction passages.
It is, therefore, a further object of this invention to provide an improved auxiliary fuel cut off system for a multi-fuel carburetor.
It is another object of the invention to provide an improved fuel cut off system for a multi-barrel, multi-fuel carburetor.
In some forms of multiple barrel carburetors, each carburetor barrel serves different engine chambers or groups of chambers. When this is done, each carburetor barrel must be provided with a complete set of discharge circuits to accommodate all running conditions. When this is done, the construction of the carburetor obviously becomes very complicated.
It is, therefore, a still further object of this invention to provide a simplified construction for a multiple barrel carburetor.